Interference detection

ABSTRACT

A wireless access point device capable of detecting out-of-band interference to the operation of the Wi-Fi network caused by LTE small cell devices such as macrocells and femtocells. A flow processor monitors the characteristics of data flows of devices connected to the wireless access point to determine whether they are LTE cells based on MAC address matching or the termination of a flow at a known mobile network operator gateway. A mitigation action to change the operational behavior of the wireless access point is then generated and applied to mitigate the effect of the detected interference device on the Wi-Fi network.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a National Phase entry of PCT Application No.PCT/EP2015/072487, filed on 29 Sep. 2015, which claims priority to EPPatent Application No. 14250110.5, filed on 30 Sep. 2014, and to EPPatent Application No. 14250112.1, filed on 30 Sep. 2014, and to EPPatent Application No. 14250111.3, filed on 30 Sep. 2014, which arehereby fully incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to wireless communications and inparticular to a method and apparatus for detecting the presence ofpotential interference sources and taking mitigating action.

BACKGROUND

In wireless communications, the IEEE 802.11 family of standards relatingto “Wi-Fi” is now a popular system for allowing devices to communicatewirelessly using radio wave transmission. Groups of devices allcommunicating via a common wireless access gateway are known as wirelesslocal area networks (WLANs).

Wi-Fi communication is licensed to operate in two sections of radiospectrum, 2.4 Ghz and 5 Ghz. At present, most devices are only able tooperate in the popular 2.4 Ghz spectrum band, while more recent devicescan also operate in the 5 Ghz band which is generally less congested.

In 2.4 Ghz Wi-Fi, the spectrum between 2402 Mhz and 2472 Mhz has beendivided into a number of channels, each channel has a central frequencyspaced 5 Mhz apart from its neighboring channel. However there isspectra overlap such that transmissions on channel 1 will interfere withtransmissions on channel 2,3,4,5, while transmissions on channel 2 willinterfere with transmissions on channels 1 and 3,4,5,6, etc.

Since there is no central controller for handling collisions in Wi-Fi,WLAN devices use a protocol known as Carrier Sense, Multiple Access withCollision Avoidance (CSMA) so that only a single device is transmittingat any one time.

CSMA is a listen-before-talk approach that attempts to determine whetherany other transmitter is operating in the Wi-Fi band. In addition Wi-Fidevices uses a variety of proprietary modulation rate adaptionalgorithms that varying the modulation and coding in accordance with theSignal to noise ratio of the channel. Both CMSA and rate adaption aredependent on the received noise level which includes interference fromother non-Wi-Fi transmitters.

In particular, the recent emergence of LTE femtocells operating in the2.3 GHz and 2.6 Ghz spectrum bands has resulted in the potential formore interference in the form of out of band interference that can causesubtle effects on Wi-Fi performance and range that are not easilydetected by the Wi-Fi devices and which can affect Wi-Fi devices indifferent ways. For example, out-of-band interference can interfere withthe automatic gain control of Wi-Fi receivers resulting in reducedsensitivity.

For example, LTE Band 7 and Band 40 lie on either side of the 2.4 GhzWi-Fi spectrum with relatively small frequency guard bands of <30 Mhz.For some Wi-Fi receivers, in particular older hardware released when thesurrounding spectrum was not generally used, having poor out-of-bandrejection, LTE transmissions in these bands can result in adjacentchannel interference affecting Wi-Fi throughput. The main effect is tocause a reduction in the Wi-Fi receiver sensitivity resulting in reducedWi-Fi range and reduced throughputs at range. In a worse case, i.e.where the LTE transmit power is high, e.g. >15 dBm and the LTEtransmitter is close to the Wi-Fi station (e.g. <1 m) then the LTEtransmissions can raise the noise floor above the carrier sensethreshold such that the Wi-Fi transmitter cannot perceive the channel asidle and so can never transmit which may result in disruption to, andpossible disconnection of the Wi-Fi link.

SUMMARY

The present disclosure is concerned with reducing the effect ofinterference on connected devices caused by nearby non-Wi-Fi devices.

In one aspect, the present disclosure provides a method of managing awireless access point device having a local network interface forwireless and wired connections via a respective wireless network andwired network, and an interface to remote networks, the wireless accesspoint being connected to at least one client device via the localnetwork interface, the method comprising: monitoring characteristics offlows of data of packets travelling between the at least one clientdevice and a remote resource located on a remote network, determiningwhether said at least one client device is an interference device whichcan affect a wireless network environment of the wireless access point;and altering a configuration of the wireless access point in response todetection of said interference device.

In another aspect, the present disclosure provides a wireless accesspoint device having a local network interface for wireless and wiredconnections via a respective wireless network and wired network, and aninterface to remote networks, the wireless access point being connectedto at least one client device via the local network interface,comprising: means for monitoring characteristics of flows of data ofpackets travelling between the at least one client device and a remoteresource located on a remote network, means for determining whether saidat least one client device is an interference device which can affectthe wireless network; and means for altering a configuration of thewireless access point in response to a determination that aninterference device is present.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described withreference and aided by the following figures in which:

FIG. 1 illustrates an overview of a network system in accordance with afirst embodiment.

FIG. 2 illustrates an ideal frequency filter which cuts out non-Wi-Fifrequencies.

FIG. 3 illustrates a typical frequency filter found in Wi-Fi equipmentshown in FIG. 1 which does not block transmissions outside of the Wi-Fifrequencies.

FIG. 4 illustrates a sample network when no interference sources arepresent.

FIG. 5 illustrates the sample network when an LTE femtocell is added tothe network.

FIG. 6 illustrates the physical components of the wireless access pointshown in FIG. 1.

FIG. 7 illustrates the functional components of the wireless accesspoint.

FIG. 8 illustrates the physical components of an interference mitigationcomponent server located in the core of the network.

FIG. 9 illustrates the physical components of an interference mitigationcomponent server located in the core of the network.

FIG. 10 is a flowchart showing the operation of the interferencedetection component.

FIG. 11 is a flowchart showing the operation of the interferencemitigation component.

FIG. 12 illustrates an overview of a network system in accordance with asecond embodiment.

FIG. 13 illustrates the functional components of a wireless access pointin the second embodiment.

FIG. 14 illustrates the functional components of an interferencemitigation component server in the second embodiment.

FIG. 15 illustrates an overview of a network system in accordance with asecond embodiment.

FIG. 16 illustrates the functional components of an interferencemitigation component server in the third embodiment.

DESCRIPTION

In the first embodiment, in order to detect potential sources ofout-of-band interference, IP traffic flows are analyzed to identifyequipment and/or network locations which are known to be associated withLTE transmissions. Examples of such detections include LTE transmitterequipment or the IP address of an LTE network's gateway servers.

FIG. 1 illustrates an overview of a network system in accordance with afirst embodiment. A user's home 1 or other local network environment isshown containing a number of networking components. A wireless accesspoint 3 such as a BT Home Hub or other similar routing device provides awireless network (WLAN) 5 to enable data connectivity between a numberof user devices 7 such as laptops, computers, smartphones and tabletswithin the home network environment. In FIG. 1, the wireless accesspoint 3 and user devices 7 within range of the WLAN 5 are wirelesslylinked using the IEEE 802.11 family of wireless protocols more commonlyknown as Wi-Fi. The WLAN 5 is configured to have a star topology inwhich each device 7 in the network 5 is wirelessly connected to thewireless access point 3 via a Wi-Fi link 9. Due to the transmissionpower and propagation limitations of Wi-Fi, the range of the wirelessnetwork 5 formed by the wireless access point 3 extends for severalmeters around the wireless access point 3 and data connectivity isgenerally limited to being within the home 1.

As is conventional, to enable communication between the devicesconnected to the WLAN 5 and external services not forming part of theWLAN 5, the wireless access point 3 also has a copper/optical fiber datalink 11 operating in accordance with the Very-High-Bitrate DigitalSubscriber Line (VDSL) standards. The copper/optical fiber data link 13connects the wireless access point 3 to an Internet Service Provider(ISP) core network 13. The ISP 13 network core provides user managementand control features for the user's account and also forwards datapackets between user devices 7 and remote devices 15 located on externalnetworks such as the Internet 17.

In addition to Wi-Fi, some user mobile devices can also use cellularnetworks provided by mobile network operators to access remote devices15 located on the Internet 17. Third generation and fourth generationcellular technologies such as High Speed Packet Access (HSPA), Long TermEvolution (LTE) and Long Term Evolution Advanced (LTE-A) are typicallyused to provide radio access network functions. eNodeBs 19 are locatedacross a geographic area to define cells spanning several squarekilometers in the mobile network operator's network (not shown) andsince eNodeBs have high transmission powers and can use a range oftransmission frequencies, cellular networks can provide wide area dataconnectivity and therefore extend into the user's home 1. The eNodeBsare connected to a mobile network operator gateway 25 of the mobilenetwork. In FIG. 1, a further user device 21 is located within the home1 but is connected to the LTE network eNodeB 19 via a LTE cellular datalink 23 instead of the wireless access point 3 via Wi-Fi. In thisembodiment, this LTE network operates at the 2.6 Ghz frequency channel.

Since LTE cellular macrocells must cover large geographic areas, thesignal quality to a mobile device varies in dependence upon the naturalterrain and man-made structures that surround a cellular device that isconnected to a macrocell. To address this, network operators can useshorter range and lower power LTE devices known as small cells whichtransmit using LTE wireless protocols over a small geographic range andwireless data is tunneled over a user's broadband connection to themobile network operator network. The term small cell devices includesdevices such as picocells, femtocells and hence is an umbrella term forshort range and low transmission power cell offload devices whichprovide a cellular signal and backhaul data to the mobile network via auser's broadband connection.

FIG. 1 also shows a LTE femtocell device 27 connected to the wirelessaccess point 3 via a wired Ethernet data link 29. The femtocell 27 isconfigured to provide LTE connectivity to LTE user devices and in FIG. 1a further user device 31 is connected to the femtocell 27 over a LTEcellular data link 33. In this embodiment, this LTE femtocell 27operates at the 2.3 Ghz frequency channel.

The LTE device 31 communicates with the femtocell 27 using LTE protocolsrather than Wi-Fi and the LTE femtocell 27 communicates with the mobilenetwork gateway 25 via the wireless access point 3 and ISP core 13.

In the environment shown in FIG. 1, there are two types of overlappingwireless networks operating under different protocols and slightlydifferent frequencies. Firstly there is a Wi-Fi network 5 operating atthe 2.4 Ghz frequency range, and secondly LTE networks operating at thelicensed spectrum bands of 2.6 Ghz and 2.3 Ghz, respectively.

The physical and spectral proximity of the LTE spectrum operatingfrequencies to the Wi-Fi operating frequency can result in interference,especially to the Wi-Fi transmissions. Cellular devices supporting the2.3 Ghz and 2.6 Ghz typically contain frequency filters which allow 2.3Ghz and 2.6 Ghz signals to pass through to the receiver while blockingsignals operating outside of the usable frequency bands. At the designstage, high quality filters are specified due to the spectral proximityof the 2.4 Ghz band which is known to be used for Wi-Fi. Therefore LTEdevices 21, 31 are generally not affected by Wi-Fi cross talk.

However, Wi-Fi equipment, and especially legacy Wi-Fi equipment isespecially prone to this type of interference since the bandpass filtersmay be inadequate for isolating the 2.4 Ghz Wi-Fi spectrum from 2.3 Ghz(LTE band 40) and 2.6 GHz (LTE band 7) LTE transmissions (which wereunused at the time such legacy equipment was manufactured).

FIG. 2 shows the ideal response of a bandpass filter installed in aWi-Fi device to prevent signals outside of the Wi-Fi spectrum frominterfering. In this ideal case, Wi-Fi frequency signals incur verylittle attenuation, while frequencies outside the Wi-Fi frequency rangeare heavily attenuated so that any transmission power in these bands isnot likely to affect the Wi-Fi signal. However, such a precise filter istypically expensive to implement due to the sharp cut off performancerequirements adding cost to the equipment.

FIG. 3 shows an example “real world” frequency response of a filtertypically installed in a wireless access point 3. In such a filter, thefiltering effect only falls away gradually resulting in a significantamount of radio frequency energy from surrounding frequency ranges beingreceived at the wireless access point 13. Therefore transmissions in theneighboring frequency bands would be received at the wireless accesspoint 3 and could have an interfering effect on the wireless accesspoint 3 performance.

Newer wireless devices, e.g. access points 3, may be able to toleratethe presence of potential interference from transmissions in neighboringfrequency ranges by using higher performance filters to reduce theeffect of the interferers. However, older wireless access points(especially those produced before the proposals for LTE bands wereproposed) typically have filters which cannot block neighboringfrequencies due to production and cost constraints. Furthermore, it isnot possible to upgrade existing legacy hardware to improve the filterperformance, especially in the case of wireless devices having internalhighly integrated receiver implementations and antennae.

Even though the two wireless communication protocols are not directlyinterfering by using the same frequencies, the general effect is thatthe LTE transmissions interfere with the automatic gain controls ofWi-Fi devices. LTE transmissions “leaking” into the Wi-Fi domain will beinterpreted by Wi-Fi devices as high background noise and thereforethese devices may alter the automatic gain control behavior of theirreceivers. Low signal to noise ratios can cause the Wi-Fi device to failto decode received packets or cause the Wi-Fi device and its peers toadopt lower modulation complexity all of which will lower the throughputcapacity of the channel. At very high levels the background noise cancause the Wi-Fi device to fail to transmit altogether. However, sinceLTE transmissions are typically bursty by nature rather than long term,as soon as the LTE transmitter stops, the Wi-Fi devices may have an overcautious modulation rate control which reduces its operating capacityfor longer periods than the actual LTE transmission.

To address this problem, the hub 3 includes an interference detectioncomponent 35 and the ISP core contains an interference mitigationcomponent 37. As will be described below, these two components interactto detect potential LTE devices which are connected to the wirelessaccess point 3 and that may cause interference to the Wi-Fi home network5. After such devices have been detected, the interference mitigationcomponent 37 determines a course of action for mitigating or otherwisereducing the effect of the LTE interference caused by the femtocell 27.In this embodiment, the interference detection component is a functionof the hub 3 and the interference mitigation component 37 is a serverlocated within the network core 13.

Overall Operation

An example of the operation of the system will now be described. FIG. 4shows a data flow diagram based on the setting shown in FIG. 1 beforethe LTE femtocell 27 has been added onto the network 1. In FIG. 1, datais being transmitted between user devices 5 and remote servers 15 viathe wireless access point 3 (hereinafter referred to as a “hub” 3) whichcontains an interference detection component 35 according to the firstembodiment and the ISP network core 13 which also contains aninterference mitigation component 37 according to the first embodiment.

A first data flow 9 a exists between device 7 a and remote server 15 aand a second data flow 9 b exists between device 7 b and remote server15 b. The data flows both traverse a packet router 41 of the hub 3, theWAN link 11 to the ISP core 13 and are routed by a network gateway 43which directs packets via an external network to the remote servers 15a, 15 b.

In this embodiment, the interference detection component 35 of the hub 3and the interference mitigation component 37 located at the network core13 function to monitor for LTE devices which are connected to the hub 3which may be potential interferers to Wi-Fi performance and to alter theoperation of the hub so that the effect of such mitigation is mitigated.The interference detection component 35 generates flow informationrelating to IP flows being carried by the hub 3 and analyzes the IP flowinformation to identify any devices currently connected to the hub whichmay cause interference to the Wi-Fi performance of the WLAN 5. Theidentification is based on matching attributes of connecteddevices/flows against a list of characteristic information.

The attributes relating to each IP flow include:

-   -   Local device MAC address;    -   Local device IP address;    -   Local device IP port;    -   Remote device MAC address;    -   Remote device IP Address;    -   Remote device IP Port;    -   Network protocol;    -   Data metrics; and    -   Timestamps.

The interference mitigation component 37 provides the matchinginformation used by the interference detection component 35 and isresponsible for selecting a mitigation action when a source ofinterference is detected by the interference detection component 35.During operation a data link 45 is present between the interferencedetection component 35 and the interference mitigation component 37.

In FIG. 4, the interference detection component 35 may determine thatthere are three data flows, two between the device 9 a and remote server15 a, two different services, as well as a further flow between device 9b and 15 b.

In the example of FIG. 4, the processing of the interference detectioncomponent determine that there are no data flows on the WLAN 5 which areindicative of interference.

FIG. 5 shows the network 1 shown in FIG. 4 after the LTE femtocell 27has been connected to the hub 3 via the Ethernet interface 29. Thefemtocell 27 provides a short range cellular data link 33 to LTE mobiledevices such as LTE enabled mobile phones 31 over a short range ofseveral meters, for example within a house. Data transmitted between theLTE mobile phone 31 and the femtocell 27 is then further forwarded viathe hub 3 and the ISP core to the mobile network gateway 25 to accessthe mobile network core and other external services.

The LTE femtocell 27 is operating in the 2.3 Ghz spectrum, and thereforecan cause interference to nearby Wi-Fi devices such as the hub 3 andmobile devices 7 a and 7 b due to the physical proximity of the LTE andWi-Fi devices 27, 3, 7 and the proximity of the spectrum ranges used bythe two wireless protocols.

In accordance with the first embodiment, the interference detectionfunction 35 is configured to monitor the devices which are connected tothe hub 3 and in particular to monitor the data flows being carried bythe hub 3 between devices.

As shown in FIG. 5, with the addition of the LTE femtocell 27 which isconnected to the mobile network gateway 25, the interference detectioncomponent 35 will determine that there is a new data flow 47 beingcarried by the hub.

The interference detection component 35 then compares the list of allflows against matching criteria. Example matching criteria may includeMAC addresses of known LTE femtocells or IP addresses of known mobilenetwork gateways.

In FIG. 5 the flow attributes of flow 47 match and therefore theinterference detection component 35 can identify LTE femtocell 27, whichis the device corresponding to the local IP address of flow 47, as beinga source of potential interference to Wi-Fi devices also connected tothe hub 3.

Having made this determination, the interference detection function 35sends information relating to the LTE femtocell 27 to the interferencemitigation component 37 via data link 45. The interference mitigationcomponent 37 receives and analyzes the received information to determinea suitable mitigation action to be carried out by the interferencedetection function 35 and hub 3 to reduce or eliminate the interferencecaused by the LTE femtocell 27 to the other Wi-Fi devices 3, 9.

In the example shown in FIG. 5, the interference mitigation component 37receives a message from the interference detection component 35containing information relating to the LTE femtocell 27. Theinterference mitigation component 37 determines properties of the LTEfemtocell. For example determining the manufacturer of the LTE femtocell27 from the MAC address of the LTE femtocell 27. Furthermore the IPaddress of the mobile network gateway 25 indicates the mobile networkoperator from which the spectrum allocations can be determined. Thedistribution of downlink and uplink packets can also be used to identifya Time Division Duplexing (TDD) LTE from a Frequency Division Duplex(FDD) LTE network. From this determination, the interference mitigationcomponent 37 obtains information that the LTE femtocell 27 is operatingin the 2.3 Ghz range.

The interference mitigation component 37 consults a mitigation listwhich specifies that the preferred resolution would be to reconfigurethe hub 3 to use a Wi-Fi channel which is spectrally further away fromthe 2.3 Ghz spectrum used by the LTE femtocell 27. The hub 3 istherefore instructed to switch to Wi-Fi channel 11 which has a centralfrequency of 2.462 Ghz. Some hubs 3 are configured to select a channelusing their own smart channel detection systems, however, the mitigationaction causes this usual behavior to be overridden.

Description of Components

FIG. 6 shows the physical components of a wireless access point 3 in thefirst embodiment. The wireless access point 3 contains a processor 51and a memory 53 for internal processing and hub functions. For externalconnectivity, the wireless access point has a Wi-Fi wireless interface55 and a wired Ethernet interface 57 for communication with other localdevices within the home network 5 and a WAN interface 59 forcommunication with remote devices via the ISP core 13, in thisembodiment the WAN interface 59 is a VDSL modem. For displayinginformation to the user of the wireless access point 3, the wirelessaccess point also has a set of status lights 61. The components areconnected via a system bus 63.

To perform the processing according to the first embodiment, the memory53 of the wireless access point 3 contains program instructions whichare executable by the processor 51 to define a number of functionalsoftware units. When these instructions are being executed, the wirelessaccess point 3 can be regarded as containing a number of functionalunits for collecting and processing data in accordance with the firstembodiment.

FIG. 7 shows the functional components of the wireless access point 3.For external connections, the wireless access point 3 has a Wi-Fiinterface 71, an Ethernet interface 73 and a WAN interface 75 eachcontaining the hardware and software functionality corresponding to thephysical Wi-Fi interface 55, Ethernet Interface 57 and xDSL modem 59,respectively. The packet routing function 41 routes packets between thedifferent interfaces.

In the first embodiment, the wireless access point 3 further includesthe interference detection component 35 for the monitoring and detectionof any potential interferers and performing mitigation actions asinstructed by the interference mitigation function 37.

The interference detection component 35 includes an IP Flow processor81, a store for the IP flow records 83. Additionally, there is amatching processor 85, a data store for rule templates 87 and a datastore containing a list of previously matched interferers 89. Aninterference notifier 91 sends the interference mitigation component 37details of any identified interferers and after processing by theinterference mitigation component 37, the wireless access point 3receives instructions from the interference mitigation component 37relating to mitigation actions based on the observed IP flows. Amitigation action processor 93 is provided to receive instructions viathe WAN interface 75 and apply the instructions to various parts of thehub 3 in order to mitigate the detected interference.

The IP Flow processor 81 is a component for analyzing the packetstravelling across the packet routing to group them into sets based on,among other parameters, their source and destination. The detected flowsare stored in the flow record store 83.

For the example situation shown in FIG. 4 where the LTE femtocell 27 isnot present, the set of active flow data collected by the IP flowprocessor and stored in the flow record store 83 may be as follows:

Total Total Timeout of Flow Flow Flow most recent ID Src IP Src PortDest IP Dest Port Proto Src MAC Bytes Packets packet 1 192.168.1.1288000 173.194.41.76 80 6 00:00:00:01:01:01 10000 100 233456789 2192.168.1.34 4333 132.146.70.61 1701 6 00:01:00:aa:bb:cc 20000 500233499999 3 192.168.1.34 5000 132.146.70.61 5000 17 00:01:00:aa:bb:cc100000 100000 233500001

In the above, IP flow #1 is an HTTP connection between device 7 a andremote device 15 a;

IP Flow #2 is a SIP VOIP TCP control connection between device 7 b andremote device 15 b; and

IP flow #3 is a SIP VOIP RTP media streamer connection between device 7b and remote device 15 b.

As shown above, each entry in the flow record store 83 contains:

-   -   A flow identity number;    -   An IP address of a local device    -   A port of the local device;    -   An IP address of the remote device;    -   A port of the remote device;    -   A protocol identifier;    -   A source MAC address;    -   The total number of bytes detected in the flow;    -   The total number of data packets transferred in the flow;    -   A timestamp of the most recent packet.

The last entry, the timestamp of the most recent packet, is used toidentify which flows are active and which ones are idle or expired. Forexample, if the difference between the current time and the most recentpacket in a flow is greater than 10 minutes then that flow is marked asinactive and is not analyzed by the other components of the interferencedetection component 35 to reduce processing load.

In this embodiment, the IP flow processor analyzes flows from devicesconnected to the wireless access point 3 via the Wi-Fi interface 71, theEthernet interface 73 and the WAN interface 75.

For the purposes of the first embodiment, the IP flow records 83 containthe identity of pairs of devices in communication of each other over agiven time period.

The matching processor 85 processes the flows in the IP Flow recordstore 83 to identify potential interferer devices attached to the homenetwork 5. The identification is carried out in accordance with datastored in the rule templates store 87 which contains matching criteriasupplied by the interference mitigation component 37. As will beexplained later, the matching rules relate to the attributes of knowninterference sources.

In the example of FIG. 4, the matching processor does not find anymatches, and therefore no further action is taken by the matchingprocessor 85 or the interference detection component 35.

However, when the LTE femtocell 27 is connected to the network as shownin FIG. 5, the IP Flow processor 81 will analyze the packet flows andadd a new entry into the IP flow records store 83 as shown below:

Total Total Timeout of Flow Flow Flow most recent ID Src IP Src PortDest IP Dest Port Proto Src MAC Bytes Packets packet 1 192.168.1.1288000 173.194.41.76 80 6 00:00:00:01:01:01 10000 100 233653721 2192.168.1.34 4333 132.146.70.61 1701 6 00:01:00:aa:bb:cc 20000 500233658134 3 192.168.1.34 5000 132.146.70.61 5000 17 00:01:00:aa:bb:cc100000 100000 233659135 4 192.168.1.32 3000 195.232.248.148 1701 50Aa:bb:ee:01:01:03 10000 200 233710389

In this case, flow 4 represents the femtocell 27 connection to themobile network gateway 25.

When the matching processor 85 next analyzes the flow records in flowstore 83, it will compare the active flows against the rule templatesstored in 87, each entry relating to a rule for identifying knowninterference devices. The matching processor 85 is configured to monitorthe flow store 83 and is triggered to analyze the flow records when achange to the flow store 83 is detected, and also every 5 minutes afterthe last trigger to process changes in flow statistics and also tohandle removal of expired flows.

An example of the rule templates is shown below:

Optional Template packet ID Source IP Source Port Destination IP DestPort IP Protocol Source MAC threshold 0 * * * * * 00:01:02:*:*:* 501 * * 195.232.248.148 1701 50 * 0 2 * * 54.194.218.211 1701 50 * 0

In the above table, at least one of the entries will contain a matchingrule while the other entries are wildcards. Template 0 contains apartial MAC address rule, devices having this partial address are knownto be LTE femtocells. Templates 1 and 2 are IP addresses of mobilenetwork gateways 25. Any flows which terminate at either of the gatewayaddresses are assumed to be LTE femtocells 27 or similar devices.

The rules in this embodiment also include an optional packet/bytethreshold which the flow packet count must exceed before the rule isdeemed to be a match. In some cases, the interference effect may bedependent on the rate of traffic generated by the interferer and lowlevels of usage may be ignored.

Using the above template rules, the matching processor 85 will determinethat the attributes of flow 4 match rule 0 and rule 1 and that thereforethis flow and the device associated with the flow is carrying LTE datawhich may interfere with Wi-Fi devices on the same network 5 and lead toincreased Wi-Fi transmission errors.

The details of the matched rule(s) are placed into the interferers list89 along with details of the type of hub 3, firmware versions andtimestamps. An example of the interferers list is shown below:

Active Interferer Access point Last Update rule(s) type FirmwareTimestamp Triggered Changed HomeHub 4 6.1.2 0 0, 1 Yes

The access point type and firmware version is included in the list sincethe mitigation action for dealing with the interference may differ independence on the type of wireless access point 3.

To save processing, at each identifying cycle, the matching processor 85also compares the new matched list against the old list previouslystored in the interferer list 89 and sets the changed field accordingly.If there is no change, then subsequent processing is not performed.

If there has been a change, for example a new matched rule has appeared(indicative of a new interferer/femtocell) or a matched rule is nolonger present (an old interferer has been removed), then the matchingprocessor forwards the list to the interference mitigation notifier 91.The interference mitigation notifier 91 sends the updated list to theinterference mitigation function 37.

Once a status message has been sent by the interference mitigationfunction 37 of the interference detection component 35, the mitigationaction processor 93 of the hub 3 waits for a response from theinterference mitigation component 37. The response will containconfiguration information for adjusting the hub 3 so that the effect ofLTE interference on the network 5 can be mitigated by reconfiguringoperational aspects of the hub 3 such are wireless channel, transmissionpower, etc.

Management Server

In this embodiment, a hub 3 is configured to communicate with theinterference mitigation component 37 located in the ISP network core 13in order to mitigate the effects of interference on Wi-Fi caused bydevices such as LTE transmitters.

It has been observed that the effect of LTE interference on a Wi-Fireceiver is dependent on a number of factors:

-   -   It is inversely proportional to the physical distance separation        between the LTE transmitter and the victim Wi-Fi receiver;    -   It is proportional to the transmit power of the LTE devices;    -   The received Wi-Fi signal power is inversely proportional to the        distance between the Wi-Fi transmitter and receiver;    -   The adjacent channel rejection performance of the Wi-Fi        receiver—i.e. its ability to filter out transmissions outside        the Wi-Fi frequency band;    -   The LTE uplink and Downlink frequencies—since some LTE frequency        configurations are closer to the Wi-Fi band and hence are more        likely to interfere;    -   The implementation of the Wi-Fi rate adaption        algorithm—different rate control algorithms react differently to        interference. Some will treat interference as an intermittent        condition and will try to keep using high data rates since they        expect the interference to be short-lived. These rate control        algorithms will behave poorly when long lived interferers such        as LTE femtocells are the interference source.

The interference mitigation component 37 is responsible for identifyingthe type of interference that a hub 3 may be experiencing, or about toexperience, and based on the determined conditions, identifying anaction that the mitigation action processor 93 of the hub 3 can take inorder to mitigate the interference.

FIG. 8 shows the physical components of the interference mitigationcomponent 37 according to the first embodiment. As shown, theinterference mitigation component 37 is embodied as a management servercontaining a processor 101, working memory 103, a persistent storagedevice 105 such as a hard drive or solid state disk, and a networkinterface 107 such as Gigabit Ethernet for communication with hubs 3 viathe ISP network 13.

When computer implemented instructions stored in the persistent datastore 105 are executed by the processor 101, the operation of theinterference mitigation component 37 can be regarded as a number offunctional units operating in accordance with the first embodiment.

FIG. 9 shows the functional units of the interference mitigationcomponent 37. The interference mitigation component 37 contains anetwork interface 111, a hub status message receiver 113, a hub messagestore 115, a mitigation action selector 117, a list of possibleinterference mitigation actions 119, a mitigation lookup database 121, ahub notifier 123, a user notifier 125, a data store containing usercontact details 127 and a list of known interference sources 129.

Hub status messages sent by the interference mitigation notifier 91within the interference detection component 35 of each hub 3 to themanagement server 17 are received by the hub status message receiver113. Status information is stored in the hub message store 105 as a hubstatus entry 131. The interference mitigation component 37 is configuredto mitigate interference for multiple hubs 3 and therefore the hubmessage store 105 will typically contain several entries relating todifferent hubs 3.

The hubs do not synchronize the sending of status messages and thereforestatus messages can be received at any time by the hub status messagereceiver 113 and stored as a hub status entry 131.

The mitigation action selector 117 is configured to periodically, forexample every 10 minutes, analyze the status message entries 131 storedin the hub message store 115 to identify the type of interference eachhub 3 is experiencing and in turn provide a mitigation action for thehubs 3 so that they can mitigate and possibly eliminate the effects ofthe LTE interference.

The mitigation action processor 117 uses the mitigation lookup database121 to match triggered interference rules contained in the hub statusentries 131 to mitigation actions stored in the list of mitigationactions 119.

The list of mitigation actions 119 contains the set of availablemitigation actions as defined by a system administrator. In the firstembodiment, the mitigation actions are defined as follows:

AP Miti- gation Action Description Comment AP0 Change Wi-Fi Changing toa different frequency Configuration e.g. channel 11 to channel 1 mayprovide improved resilience to LTE Band 7 AP1 Enable InterferenceDisplays a warning page on the Detected Indication - Access Point webadmin page Admin page AP2 Enable Interference Enable a LED warning lighton the Detected Indication - Wi-Fi access point Hub light AP3 Installfirewall rule Install a new firewall rule to block or restrict theinterferer traffic AP4 Apply rate limit Install a throughput rate limiton the interferer traffic flow to limit its interference effect AP5Change Wi-Fi driver A change to the configuration of the parameter. E.g.short/ Wi-Fi driver e.g. reduced number of long retry, RTS retries,reduced use of frame aggre- threshold, Max gation to reduce the impactof the AMPDU, as well as interference, increased Tx power. proprietarychipset Different Wi-Fi chipsets may provide specific parametersproprietary noise immunity features which can be enabled. AP6 Initiatefirmware Start the firmware upgrade process upgrade

As shown the actions can be generally split into 2 classes,reconfiguring the wireless operational characteristics of the hub 3; andindirectly affecting the operation of the potentially interfering deviceby limiting the flow of data from the LTE device 27.

In some cases, the selected mitigation action also requires a degree ofuser action such as moving the interfering device further away from thehub and therefore the list of interference mitigation actions 119 alsocontains user alerting actions.

User mitigation action Description User0 Email owner at their registeredaddress User1 SMS owner at registered mobile/fixed phone number User2In-app message via Apple Push notification or Google Cloud to devicemessaging

The mitigation lookup database 121 contains entries which allow themitigation action processor 117 to match triggered rules to actions. Anexample database is shown below. The database can be periodicallyupdated by a system administrator to include new equipment entries andalso to reconfigure the mappings.

Interferer rule Mitigation Hub Type Firmware triggered actions Priority4a * 0 AP2 1 4a * 1 AP0 3 4a * 2 AP5, User0 2 5a 6.1 0 AP6 1 * * 1 AP5 23a * * AP3, AP1 1

The mitigation action processor 117 uses the hub type in the hub statusentry 131 as the index into the database followed by the firmwareversion. Next the triggered rules are identified before locating anappropriate mitigation action.

Since several rules can be triggered and therefore contained in the hubstatus message, the mitigation action processor identifies all of theentries in the mitigation lookup database which match the triggeredrules. Since this may lead to different mitigation actions, in thisembodiment, to avoid too many, and possibly conflicting, reconfigurationactions, each entry in the mitigation lookup database 121 has a priorityand the mitigation action processor 117 is configured to only select theaction with the highest priority for the hub configuration.

For example, in the case of the hub status entry 131 indicating thatrule 1 was triggered, the potentially interfering device 27 is connectedto a mobile network gateway 25. Since the IP address of the mobilenetwork gateway 25 is known, the LTE frequency configuration being usedby the femtocell can be determined because the LTE licensed frequenciesare publically known.

In the example for this mobile gateway 25 e.g. Vodafone, the action inthe mitigation lookup database 121 is to change the Wi-Fi channel tomaximize the spectral distances. In the case of another gateway, forexample EE, using a close LTE frequency, then a mitigation solutioninvolving physical separation of the femtocell and wireless access pointwill be necessary.

The mitigation action processor 117 takes the selected mitigation actionas determined from the highest priority mitigation lookup entry. Theselected action is passed to the hub notifier 123 which sendsinstructions to the relevant hub 3. These instructions may be suppliedto the AP either as a response to the initial sending of the hub statusmessage which is an http request or may be applied by other access pointconfiguration management systems such as TR 069 based hub configuration.

If any user actions are included in the selected mitigation action, thehub notifier 123 passes that action to the user notifier 125. The usernotifier 125 contains relevant applications for sending emails, sendingtext messages and notifying the user using details stored in the usercontact details store 127.

Implementing the Mitigation Action

Returning to FIG. 7, the message from the hub notifier 123 is receivedby the mitigation action processor 93 of the interference detectioncomponent 35.

The mitigation action processor 93 interprets the instruction andchanges the configuration of the hub to mitigate the potentialinterference. Typically this is by changing operating parameters of thewireless interface.

Updates

The rules used by the interference detection component 35 of the hub 3are stored in the interferers list 89. These are periodically updated asnew interferers discovered. Returning to FIG. 9, the interferencemitigation component 37 contains a list of known interference sources129 which is updated by a system administrator to allow new interferersto be detected so that a mitigation action can be selected.

The list is periodically sent out to the hubs 3 by the hub notifier 129.This message is received by the mitigation action processor 93 whichthen updates the rule templates 87 for that hub 3.

Flowcharts

FIG. 10 shows a flowchart of the operation of the interference detectioncomponent 35 of the hub 3 in accordance with the first embodiment. Ins1, the IP flow processor 81 processes the current IP flows beingcarried by the packet routing 41 of the hub and stores them in the IPflow records 83. s1 is carried out whenever a new flow is detected, andalso periodically so that the IP flow information is current. In s3 anyinactive flows are removed from further consideration.

In s5, the matching processor 85 compares the list of active flowsagainst the information in the rules template 87 to identify possibleinterferers 27 connected to the hub 3 and generates a list of matchedinterference in s7. The results are stored in the interferers list 89.To reduce processing, in s9, the matching processor 85 also compares thegenerated list against the old list of interferers to detect changescompared with the previous detection. A test is performed in s11 todetermine whether any changes were detected in s9. If there are nochanges, then processing ends. However, if the list has changed, thenthis is indicative that an interference source has been added, or hasbeen removed from the home network 5. Therefore the interferencemitigation component should be informed so that a new mitigationsolution can be determined based on the new interference environment ofthe home network 5.

In s13 the list is marked as changed by the matching processor 85 andthen in s15 the interference mitigation notifier 91 receives theinterference list and sends the list to the interference mitigationcomponent 37.

After a time, in s17, the response from the interference mitigationcomponent 37 and in s19 the mitigation action processor 93 processes theresponse and carries out the mitigation action instructions. Processingthen ends for this analysis phase of the home network 5.

FIG. 11 is a flowchart showing the processing of the interferencemitigation component which is located in the ISP network core 13 in thefirst embodiment.

In s21, the hub status message receiver 113 receives a message from theinterference mitigation notifier 91 of a hub 3. In s23, the received hubstatus information is stored in hub message store 115 with other hubmessage stores 131.

In s25, the mitigation action selector 117 processes the hub messages131 in accordance with the mitigation lookup database 121 and the listof interference mitigation actions 119 to identify the type ofinterference and identify a mitigation instruction for the hub 3,respectively.

In s27, the hub notifier 123 sends mitigation messages to the hub 3 andprocessing ends for that particular hub.

Summary of the First Embodiment

In the first embodiment, a system is disclosed in which the interferencedetection component 35, located at the hub 3, uses inspection of IPtraffic flows traversing the Wi-Fi access point/DSL modem/Broadbandnetwork to identify potential sources of interference within the home 1.The interference mitigation component 37 maintains a list ofinterference mitigation solutions and identifies whether the trafficflows traversing the hub are indicators of a potential Wi-Fiinterference source and if so, determines a recommended mitigationaction should be. The selected mitigation solution is then sent toeither:

-   -   The access point for a configuration change; or    -   The owner/administrator of the access point.

The advantages provided by the system of the first embodiment include:

-   -   the ability to identify sources of interference within the home        which are not visible to the Wi-Fi receiver in the AP but which        can potentially affect the performance of other Wi-Fi devices in        the home;    -   can perform the identification without requiring additional        radio layer signal processing techniques;    -   does not require additional hardware changes and so can be        deployed with legacy equipment;

Second Embodiment

In the first embodiment, the interference detection component isconfigured to determine whether there are any potentially inferringdevices connected to a hub and the interference mitigation componentdetermines an appropriate response to mitigate the interference. Incases where the hub is not connected to any interfering devices, thathub will not report any interfering devices to the interferencemanagement component.

However, where the hubs are in close proximity to each other, forexample in densely populated areas, it is likely that the detectedinterference source affecting the connected hub will probably affectneighboring hubs, too.

FIG. 12 shows an example network system in the second embodiment.

In the network of FIG. 12, a number of hubs 201 a-201 f are shown havingwireless access points 203 to generate wireless LANs 205. Some of thehubs 201 a, 201 b, 201 e, also have small cells 207 attached to them.For example, a first hub 201 a has a femtocell 207 a, second hub 201 bhas a femtocell 207 b and third hub 201 e has a picocell 207 c.

Each hub 201 carries out the processing as per the first embodiment inorder to notify an interference mitigation component 209 located withinthe network core 211 as to whether a known interference device has beendetected, i.e. an LTE small cell (femtocells and picocells).

Three of the hubs 201 a, 201 b, 201 e will report the presence of aninterferer since the processing of the interference detection componentof each hub is the same as in the first embodiment. Subsequently, theinterference mitigation component 209 will process the receivedinterference message from each of the hubs 201 a, 201 b and 201 e andsend mitigation instructions to those particular hubs 201 a, 201 b, 201e which reported an interference source.

Therefore the configuration of hubs 201 a, 201 b, 201 e which reportedan interference source will be changed, for example by changing aconfiguration of the wireless access point 203 a, 203 b, 203 e of eachhub.

However, if a small cell has a range such that it can affect neighboringhubs, those hubs will not be able to report any interference sources. Inthe example system of FIG. 12, hub 201 c is within range of thefemtocell 207 a attached to hub 201 a, and hub 201 d is within the rangeof the picocell 207 e attached to hub 201 e.

To address these hubs 201 c, 201 d, in the second embodiment, each hub201 is arranged to scan the local wireless environment to detect thepresence of surrounding hubs and then pass the scan results to theinterference mitigation component 209 at the same time as sending aninterference status message.

The interference mitigation component 209 is then arranged to determinewhether the detected neighbor hub is likely to be affected by theinterference and if so, to send that hub a mitigation action.

FIG. 13 shows the functional components of each hub 201 in the secondembodiment.

For external connections, the wireless access point 201 has a Wi-Fiinterface 231 connected to an antenna 221, an Ethernet interface 233 anda WAN interface 235. A packet routing function 229 routes packetsbetween the different interfaces.

In the first embodiment, the wireless access point 3 further includesthe interference detection component 227 for the monitoring anddetection of any potential interferers and performing mitigation actionsas instructed by the interference mitigation function 209.

The interference detection component 227 includes an IP Flow processor237, a store for the IP flow records 239. Additionally, there is amatching processor 241, a data store for rule templates 243 and a datastore containing a list of previously matched interferers 245. Aninterference notifier 247 sends the interference mitigation component209 details of any identified interferers and after processing by theinterference mitigation component 209, the hub 201 receives instructionsfrom the interference mitigation component 209 relating to mitigationactions based on the observed IP flows. A mitigation action processor249 is provided to receive instructions via the WAN interface 235 andapply the instructions to various parts of the hub 201 in order tomitigate the detected interference.

The components of the hub 201 in the second embodiment are generallysimilar to their equivalent components in the first embodiment.

The interference mitigation notifier 247 differs only in that aregistration process is carried out when the hub 201 is turned on toprovide the interference mitigation component 209 details of that hub'sBSSID, MAC address and current Wi-Fi operating channel frequency.

The Wi-Fi interface 231 is further configured to periodically switchinto client mode and conduct a scan for surrounding hubs. For anyobserved access points, BSSID and signal strengths and Wi-Fi ChannelFrequency are recorded and stored in a Wi-Fi scan store 251.

When the processing of the matching processor 241 determines that aninterfering LTE small cell device is present, the hub status message iscompiled and sent to the interference mitigation notifier 247. Theinterference mitigation notifier 247 is configured in this embodiment tosend the list of detected surrounding hubs and the hub status message tothe interference mitigation component 209.

FIG. 14 shows the functional components of the interference mitigationcomponent 209.

The interference mitigation component 209 is generally similar to theinterference mitigation component 37 of the first embodiment. It has thesame physical components as shown in FIG. 8 and similar functionalcomponents to those shown in FIG. 9. The interference mitigationcomponent 209 of the second embodiment contains a network interface 261,a hub status message receiver 263, a hub message store 265, a mitigationaction selector 267, a list of possible interference mitigation actions269, a mitigation lookup database 271, a hub notifier 273, a usernotifier 275, a data store containing user contact details 277 and alist of known interference sources 279. These components function in thesame manner as the network interface 111, a hub status message receiver113, a hub message store 115, a mitigation action selector 117, a listof possible interference mitigation actions 119, a mitigation lookupdatabase 121, a hub notifier 123, a user notifier 125, a data storecontaining user contact details 127 and a list of known interferencesources 129 of the interference mitigation component 37, respectively,and therefore their operation will not be described again.

The interference mitigation component 209 also contains a hub neighborprocessor 281 and a hub directory 283 to handle neighbor hubs.

The hub status message receiver 263 is further configured to receive thehub registration messages and store the messages into hub directory 283.Hub directory 283 therefore contains information relating to the BSSIDand Wi-Fi operating channel of each connected hub even if they do notreport interfering devices.

In accordance with the example system shown in FIG. 12, hub directory283 contains the following information.

Hub identifier BSSID MAC address Wi-Fi frequency (Ghz) Hub_201aBTHub5-201a MAC201a 2.412 Hub_201b BTHub3-201b MAC201b 2.437 Hub_201cBTHub4-201c MAC201c 2.472 Hub_201d BTHub5-201d MAC201d 2.422 Hub_201eBTHub2-201e MAC201e 2.437 Hub_201f BTHub2-201f MAC201f 2.412

Any neighbor scan information is also stored into the device messagestore 265 for any hub which notifies the interference mitigationcomponent 209 of interference.

For example, the entry for hub 201 a would contain the following scaninformation.

-   -   ID—Hub_201 a    -   Scan result 1        -   BSSID—Hub_201 c        -   Signal Strength −50 dBm        -   MAC Address—MAC201 c        -   Channel Frequency 2412 MHz

The entry for hub 201 b will contain the following scan information

-   -   ID—Hub_201 b    -   Scan result 1        -   [null]

The entry for hub 201 e will contain the following information

-   -   ID—Hub201 e    -   Scan result 1        -   BSSID—Hub_201 d        -   Signal Strength −60 dBm        -   MAC address—MAC201 d        -   Channel Frequency 2462 MHz

Hubs 201 b, 201 d and 201 f do not have entries since they are notconnected to any interfering devices.

The hub neighbor processor 281 is responsible for determining whetherany neighbor hubs are present and likely to be affected by aninterference source associated with another hub. Considering the scan onhub 201 a, the hub population processor will check whether a hub hasbeen detected, in this case hub 201 c, and then assess the signalstrength and Wi-Fi channel frequency observed in the Wi-Fi scan. Sincethe strength is −50 dBm and the Wi-Fi frequency is close to, e.g. a 2.3GHz small cell 207 a, the hub 201 c is determined to be likely to beaffected by the small cell 207 a attached to hub 201 a.

The hub neighbor processor 281 then generates a hub notificationmessage, generally containing the same mitigation action as the actionselected by the mitigation action selector 267, and the hub notifier 273sends the generated hub notification message to the neighbor hub 201 cvia a standard hub remote management system such as TR069.

Similar processing will be carried out by the hub neighbor processor 281for the sending a mitigation action to hub 203 d.

In the second embodiment, the neighbor of hubs 201 to hubs having LTEinterference sources 207 can be detected and a mitigation action can besent to those neighbors in order to mitigate the effect of nearby LTEinterference which would not be detected in the first embodiment.

Third Embodiment

In the third embodiment, the interference mitigation component islocated within the network core and is configured to perform hubprocessing as in the first embodiment for connected hubs, but is furtheroperable to detect hubs which may be affected by a neighbor hub's smallcell. The interference mitigation component includes additionalprocessing to determine the geographical location of the connected hubsand apply group processing of the connected hub interference informationso that mitigation information can be sent to groups of neighboringhubs.

FIG. 15 shows an overview of the network system in the third embodiment.

In the network of FIG. 15, which is similar to the network shown in FIG.12 of the second embodiment, a number of hubs 301 a-301 f are shownhaving wireless access points 303 to generate wireless LANs 305. Some ofthe hubs 301 a, 301 b, 301 e, also have small cells 307 attached tothem. For example, a first hub 301 a has a femtocell 307 a, second hub301 b has a femtocell 307 b and third hub 301 e has a picocell 307 c.

Each hub 301 carries out the processing as per the first embodiment inorder to notify an interference mitigation component 309 located withinthe network core 311 as to whether a known interference device has beendetected, i.e. an LTE small cell (femtocells and picocells).

Three of the hubs 301 a, 301 b, 301 e will report the presence of aninterferer since the processing of the interference detection componentof each hub is the same as in the first embodiment. Subsequently, theinterference mitigation component 309 will process the receivedinterference message from each of the hubs 301 a, 301 b and 301 e andsend mitigation instructions to those particular hubs 301 a, 301 b, 301e which reported an interference source.

Therefore the configuration of hubs 301 a, 301 b, 301 e which reportedan interference source will be changed, for example by changing aconfiguration of the wireless access point 303 a, 303 b, 303 e of eachhub.

However, if a small cell has a range such that it can affect neighboringhubs, those hubs will not be able to report any interference sources. InFIG. 15, hub 301 c is within range of the femtocell 307 a attached tohub 301 a, and hubs 301 d and 301 f are within the range of the picocell307 e attached to hub 301 e.

In the third embodiment, the interference mitigation component 309 isconfigured to identify such situations where a small cell 307 may causeinterference to its attached hub 301 and also to neighboring hubs 301.

In response to this identification, the interference mitigationcomponent will push mitigation instructions to those affected hubs sothat they can, for example, alter their wireless access pointconfiguration.

In this way, the interference mitigation component 309 provides acentralized interference mitigation function for a population of hubs301.

The hubs 301 are configured with the same components as described in thefirst embodiment, the interference detection component 35 of each hubalso operates in the same manner as described in the first embodimentwith the exception that hubs perform a simple registration process atstart up to log their MAC and IP address with the interferencemitigation server 309 in the manner described in the second embodiment.

FIG. 16 shows the functional components of the interference mitigationcomponent 309 in the third embodiment.

The interference mitigation component 309 is generally similar to theinterference mitigation component 37 of the first embodiment. It has thesame physical components as shown in FIG. 8 and similar functionalcomponents to those shown in FIG. 9. The interference mitigation server309 of the third embodiment contains a network interface 321, a hubstatus message receiver 323, a hub message store 325, a mitigationaction selector 327, a list of possible interference mitigation actions329, a mitigation lookup database 331, a hub notifier 333, a usernotifier 335, a data store containing user contact details 337 and alist of known interference sources 339. These components function in thesame manner as the network interface 111, a hub status message receiver113, a hub message store 115, a mitigation action selector 117, a listof possible interference mitigation actions 119, a mitigation lookupdatabase 121, a hub notifier 123, a user notifier 125, a data storecontaining user contact details 127 and a list of known interferencesources 129 of the interference mitigation server respectively andtherefore their operation will not be described again.

In the third embodiment, the interference mitigation component 309includes an action history store 341, a hub population processor 343 anda hub location store 345.

The action store history 343 contains a log of the output of themitigation action processor 327 for all hubs. Each time the mitigationaction processor 327 generates a new action for a particular hub 301,the output is sent to both the hub notifier 333 and the action storehistory 343.

In accordance with the system of FIG. 15, the action store history 343may contain:

Timestamp Hub ID Action TS 1 hub_301a AP2 TS240 hub_301b AP5 TS278hub_301e AP1

The hub location store 345 contains information relating to thegeographic location of all the connected hubs. This location informationis populated in advance, for example by a system administrator for eachconnected hub using customer address information or by receipt ofposition information (determined by built in GPS or using Wi-Fifingerprinting techniques) from a mobile app running on a mobile deviceconnected to a hub. Each entry also contains the current IP and MACaddress pairs received during hub registration.

In the system of FIG. 15, the hub population store 345 may contain:

HubID IP address MAC Location Type Hub_301a HubIP301a HubMAC301acoordinate pair_a Hub5 Hub_301b HubIP301b HubMAC301b coordinate pair_bHub2 Hub_301c HubIP301c HubMAC301c coordinate pair_c Hub3 Hub_301dHubIP301d HubMAC301d coordinate pair_d Hub4 Hub_301e HubIP301eHubMAC301e coordinate pair_e Hub3 Hub_301f HubIP301f HubMAC301fcoordinate pair_f Hub2

The hub population processor 343 is configured to analyze the mitigationaction store 341, for example every 15 minutes, or as each new entry iscreated, to create a list of active hubs 301 which have been sentmitigation actions.

As mentioned above, the mitigation action processor 327 will havealready sent mitigation instructions to the hubs which have indicated anew interferer has been detected on that hub's home network. However,hubs which are nearby these affected hubs will not detect anyinterferers but may nonetheless suffer interference.

The hub population processor 343 therefore sends a request to the hublocation store 345 containing the list of IP addresses of hubs affectedby interference in order to retrieve the identity of hubs which arelocated near to those affected hubs.

In the example scenario shown in FIG. 15, when the hub populationprocessor 343 sends a request to the hub location store 345 to retrievethe identity of hubs close to hubs 201 a, 201 b and 201 e, the hublocation store 345 would retrieve the following results.

Input hub Nearby hubs hub 301a hub 301c hub 301b none hub 301e hub 301d,hub 301f

The definition of nearby used by the hub location store 345 can vary independence on the type of interference device detected. For example,femtocells 307 a and 307 b have short ranges and therefore 10 m is theexpected range. Therefore the hub location store would only search forhubs within 10 m of the affected hub 301 a. However, hub 301 e isattached to a picocell 307 c which has a range of up to 200 m andtherefore the threshold for “nearby” is greater.

The type of hub is also considered by the hub location store 345 sinceolder hubs are more susceptible to interference than modern hubs.

Once the list of nearby hubs has been retrieved, the hub populationprocessor 343 sends mitigation instructions to the identified neighborhubs via the hub notifier 333. In this embodiment, the mitigationinstruction is the same as the instruction identified by the mitigationaction processor 327.

The processing in this embodiment is intensive on the resources of theinterference mitigation component 309 due to the identification ofnearby hubs in the hub location store 345. However, with the processingof the interference mitigation component 309 in the third embodiment,further hubs possibly affected by LTE cells can have their configurationaltered compared with detection based on what other access points a hubcan detect. For example, in this embodiment, the configuration of hub301 f will be changed since it is deemed to be close to the interferenceof hub 301 e. This behavior is a contrast to the second embodiment,where the equivalent to hub 301 f would not have been detected as apossible neighbor because it is outside the scannable Wi-Fi range of thehub 301 e.

Alternatives and Modifications

In the embodiment, the interference detection component is located atthe hub and the interference mitigation component is located at a serverin the network core.

Other configurations are possible while still falling within the scopeof the disclosure. In a first alternative, the interference detectioncomponent, including flow detection, is implemented remotely in a serverin the ISP network core rather than in the hub. This reduces theprocessing requirements at the hub at the expense of more control datatransfer over the broadband connection.

Each hub only requires a mitigation action receiver. The rest of theinterference detection component and interference mitigation componentfunctions are performed at the server for all hubs.

In a further alternative, the interference detection component and themitigation processing component are both implemented at each hub. Inthis way, each hub is capable of detecting and resolving interferencedevices connected to the local area network of the hub. The localprocessing allows the resolution to be implemented more quickly comparedto the previous embodiments. A management server is only required tostore the master set of interferer detection rules and the set ofmitigation actions. The updated data in these stores is periodicallypushed to each hub.

In the embodiment and above alternatives, the detection of potentiallyinterfering devices is performed by analyzing the IP flows. Suchprocessing can detect potentially interfering devices which areconnected to the home network, but cannot detect other sources of LTEinterference. For example the LTE macrocell 19 which is operating at the2.6 GHz frequency and therefore can interfere with 2.4 Ghz Wi-Fi. Theprocessing of the above embodiments will not detect the macrocell 19. Inan alternative, the hub includes, or is connected to, dedicated wirelesssignal sensing hardware located on the home network which uses air wavescanning techniques to detect interferers. This information is used tosupplement the interference detection component to detect more sourcesof interference.

Alternatively, mobile devices having both LTE and Wi-Fi capabilitiescould be used to scan the surrounding area for macrocells and Wi-Fineighbors. A mobile application installed on the mobile device can beconfigured to record any observed LTE cells, both macro and small, andWi-Fi signals, along with signal strength and forward the collectedinformation to the interference mitigation component.

In a further modification, the interference mitigation component willaccess location information regarding the location of the macrocells inorder to identify hubs which may be affected by LTE interference causedby the macrocell. The macrocell information can be included in themitigation selection stage to determine an appropriate mitigationaction.

In the second embodiment, the neighbor detection is carried out on thebasis of Wi-Fi scans performed by the hubs and reported to theinterference mitigation component to detect relative positions between ahub and its neighbors. In the third embodiment, neighbors are detectedbased on knowledge of the absolute position of the hubs. In analternative, a combination of relative and absolute positioning is usedbased on the second and third embodiment so that immediate neighbors canbe quickly updated with mitigation action, while the slower and moreprocessing intensive neighbor search can be implemented later.

In the embodiments, the small cells are connected to the hubs via theEthernet interface so that LTE cellular data transfer is from LTEdevices to small cell via LTE, then from the small cell to the hub viaEthernet, and then from the hub to the network core via xDSL.

In an alternative, the small cell is connected to the hub via analternate Wi-Fi frequency band or wireless data transfer protocol, e.g.5 Ghz which offers increased bandwidth and reliability. In this way, theLTE cellular data transfer is from LTE devices to small cell via LTE,then from the small cell to the hub via Wi-Fi, and then from the hub tothe network core via xDSL.

The invention claimed is:
 1. A method of managing a wireless accesspoint device having a local network interface for wireless and wiredconnections via a respective wireless network and wired network, and aninterface to remote networks, the wireless access point being connectedto at least one client device via the local network interface, themethod comprising: monitoring characteristics of flows of data ofpackets traveling between the at least one client device and a remoteresource located on a remote network; determining, based on themonitoring, whether said at least one client device is an interferencedevice which can affect a wireless network environment of the wirelessaccess point; and altering a configuration of the wireless access pointin response to determining that said at least one client device is aninterference device.
 2. A method according to claim 1, wherein themonitored characteristics include hardware device identifier informationand logical network address identifier information of the devicesforming the end points of the data flow.
 3. A method according to claim1, wherein the at least one client device is identified as aninterference device when the flow characteristics match a set ofcharacteristics relating to known interference devices.
 4. A methodaccording to claim 1, wherein the at least one client device is acellular communication device connected to the wired network of thewireless access point.
 5. A method according to claim 4, wherein thecellular communication device is a short range cell device operating inaccordance with the Long Term Evolution (LTE) set of protocols.
 6. Amethod according to claim 1, further comprising selecting a mitigationaction from a set of locally stored mitigation actions.
 7. A methodaccording to claim 1, further comprising: sending information relatingto the identified interferer device to a remote server; and receiving amitigation instruction.
 8. A wireless access point device having a localnetwork interface for wireless and wired connections via a respectivewireless network and wired network, and an interface to remote networks,the wireless access point being connected to at least one client devicevia the local network interface, the wireless access point comprising: aprocessor and a memory, the processor configured to: monitorcharacteristics of flows of data of packets traveling between the atleast one client device and a remote resource located on a remotenetwork; determine, based on the monitored characteristics, whether saidat least one client device is an interference device which can affectthe wireless network; and alter a configuration of the wireless accesspoint in response to determining that said at least one client device isan interference device.
 9. A wireless access point according to claim 8,wherein the processor is configured to monitor characteristics includinghardware device identifier information and logical network addressidentifier information of the devices forming the end points of the dataflow.
 10. A wireless access point according to claim 8, wherein theprocessor is configured to identify the at least one client device as aninterference device when the flow characteristics match a set ofcharacteristics relating to known interference devices.
 11. A wirelessaccess point according to claim 8, wherein the at least one clientdevice is a cellular communication device connected to the wired networkof the wireless access point.
 12. A wireless access point according toclaim 11, wherein the cellular communication device is a short rangecell device operating in accordance with the Long Term Evolution (LTE)set of protocols.
 13. A wireless access point according to claim 8,wherein the processor is further configured to select a mitigationaction from a set of mitigation actions stored in the memory.
 14. Awireless access point according to claim 8, further comprising acommunication interface configured to: send information relating to theidentified interference device to an interference mitigation server; andreceive a mitigation instruction from said interference mitigationserver.
 15. A non-transitory computer-readable storage medium storing acomputer program comprising instructions that when executed by acomputer apparatus control the computer apparatus to perform the methodof claim 1.